U.S. patent application number 17/308839 was filed with the patent office on 2021-08-26 for optoelectronic component, organic functional layer, and method for producing an optoelectronic component.
The applicant listed for this patent is OSRAM OLED GmbH. Invention is credited to Arndt Jaeger, Gunter Schmid.
Application Number | 20210265577 17/308839 |
Document ID | / |
Family ID | 1000005567785 |
Filed Date | 2021-08-26 |
United States Patent
Application |
20210265577 |
Kind Code |
A1 |
Jaeger; Arndt ; et
al. |
August 26, 2021 |
Optoelectronic Component, Organic Functional Layer, and Method for
Producing an Optoelectronic Component
Abstract
In an embodiment a method for producing an optoelectronic
component includes providing a substrate, forming a first
electrode, depositing an organic functional layer or a plurality of
organic functional layers over the substrate by simultaneous
vaporization from different sources of a first compound and of a
second compound and of a matrix material and forming a second
electrode, wherein at least one coordinate bond is formed by the
first compound with the second compound and by the first compound
with the matrix material and/or by the second compound with the
matrix material.
Inventors: |
Jaeger; Arndt; (Regensburg,
DE) ; Schmid; Gunter; (Hemhofen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OSRAM OLED GmbH |
Regensburg |
|
DE |
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|
Family ID: |
1000005567785 |
Appl. No.: |
17/308839 |
Filed: |
May 5, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14895486 |
Dec 2, 2015 |
11038127 |
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PCT/EP2014/063410 |
Jun 25, 2014 |
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17308839 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 51/5096 20130101;
H01L 51/56 20130101; H01L 51/0091 20130101; H01L 51/0058 20130101;
H01L 51/009 20130101; H01L 51/506 20130101; H01L 51/5088 20130101;
H01L 51/0072 20130101; H01L 51/5056 20130101; H01L 51/006 20130101;
H01L 51/0051 20130101; H01L 51/001 20130101 |
International
Class: |
H01L 51/00 20060101
H01L051/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2013 |
DE |
102013106949.5 |
Claims
1. A method for producing an optoelectronic component, the method
comprising: providing a substrate; forming a first electrode;
depositing an organic functional layer or a plurality of organic
functional layers over the substrate by simultaneous vaporization
from different sources of a first compound and of a second compound
and of a matrix material; and forming a second electrode, wherein
at least one coordinate bond is formed by the first compound with
the second compound and by the first compound with the matrix
material and/or by the second compound with the matrix
material.
2. The method according to claim 1, wherein the organic functional
layer is arranged between the first electrode and the second
electrode.
3. The method according to claim 1, wherein the first compound
interacts with the second compound, wherein the first compound
and/or the second compound interacts with the matrix material, and
wherein the interactions generate conductivity in the organic
functional layer.
4. The method according to claim 1, wherein the first compound
comprises an electron acceptor in relation to the matrix material
and/or an electron acceptor in relation to the second compound.
5. The method according to claim 1, wherein an electron
donor-electron acceptor complex is formed by interaction of the
first compound with the second compound in a gas phase.
6. The method according to claim 1, wherein the first compound
forms an electron donor-electron acceptor complex with the second
compound via at least one coordinate bond.
7. The method according to claim 1, wherein the first compound
forms at least one coordinate bond with the second compound to
provide a chainlike structure and/or a netlike structure.
8. The method according to claim 1, wherein at least one coordinate
bond is formed by the first compound with the second compound and
at least one coordinate bond is formed by the first compound with
the matrix material, or wherein at least one coordinate bond is
formed by the first compound with the second compound and at least
one coordinate bond is formed by the second compound with the
matrix material.
9. The method according to claim 1, wherein the first compound
comprises a metal complex having at least one central metal
atom.
10. The method according to claim 9, wherein the central metal atom
of the first compound comprises an element selected from the group
consisting of Cu, Cr, Mo and Bi.
11. The method according to claim 1, wherein the first compound
comprises a compound selected from the group consisting the
following structural units or formulae: ##STR00012## wherein, in
formulae I and II, R.sub.1, R.sub.1', R.sub.2x and R.sub.2x' are
independent of one another and each is selected from the group
consisting of unbranched, branched, fused, cyclic, unsubstituted
and substituted alkyl radicals, substituted and unsubstituted
aromatics, and substituted and unsubstituted heteroaromatics,
wherein x in each case is a, b, c or d, wherein, in formulae III
and IV, R.sub.1, R.sub.2, R.sub.3 and/or R.sub.4 are identical or
unidentical and each is selected from the group consisting of
substituted or unsubstituted hydrocarbon radicals, alkyl radicals,
cycloalkyl radicals, heterocycloalkyl radicals, aryl radicals,
heteroaryl radicals, and combinations thereof, and wherein the
second compound comprises a compound selected from the group
consisting of
dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile,
7,7,8,8-tetracyanoquionodimethane,
2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane,
2,3-di(N-phthalimido)-5,6-di-cyano-1,4-benzoquinone,
pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile and
fluorinated or unfluorinated derivatives thereof, and
tetracyanonaphthoquinodimethane and fluorinated or unfluorinated
derivatives thereof.
12. The method according to claim 1, wherein the second compound
comprises an aromatic and/or heteroaromatic that has at least two
functional groups that are capable of forming a coordinate bond
and/or of .pi.-.pi. interaction.
13. The method according to claim 12, wherein the functional groups
comprises functional groups selected from the group consisting of
amine, phosphine, phenol, thiol, cyano, isocyano, cyanato, nitrato,
carboxylato, fluorinated carboxylato, acetylacetonate, fluorinated
acetylacetonate, carbonal, amide, imide, thienyl, fluoro, and
combinations thereof.
14. An optoelectronic component comprising: a substrate; a first
electrode; a second electrode; and an organic functional layer
arranged between the first electrode and the second electrode,
wherein the organic function layer comprises a matrix material, a
first compound, and a second compound, wherein the first compound
interacts with the second compound, wherein the first compound
and/or the second compound interacts with the matrix material,
wherein the interactions generate conductivity in the organic
functional layer, and wherein the first compound comprises an
electron acceptor in relation to the matrix material and/or an
electron acceptor in relation to the second compound.
15. The optoelectronic component according to claim 14, wherein the
organic functional layer comprises a layer selected from the group
consisting of a hole transport layer, a hole injection layer, and a
hole blocking layer.
16. The optoelectronic component according to claim 14, wherein the
first compound comprises a compound selected from the group
consisting the following structural units or formulae: ##STR00013##
wherein, in formulae I and II, R.sub.1, R.sub.1', R.sub.2x and
R.sub.2x' are independent of one another and each is selected from
the group consisting of unbranched, branched, fused, cyclic,
unsubstituted and substituted alkyl radicals, substituted and
unsubstituted aromatics, and substituted and unsubstituted
heteroaromatics, wherein x in each case is a, b, c or d, wherein,
in formulae III and IV, R.sub.1, R.sub.2, R.sub.3 and/or R.sub.4
are identical or unidentical and each is selected from the group
consisting of substituted or unsubstituted hydrocarbon radicals,
alkyl radicals, cycloalkyl radicals, heterocycloalkyl radicals,
aryl radicals, heteroaryl radicals, and combinations thereof, and
wherein the second compound comprises a compound selected from the
group consisting of
dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile,
7,7,8,8-tetracyanoquionodimethane,
2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane,
2,3-di(N-phthalimido)-5,6-di-cyano-1,4-benzoquinone,
pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile and
fluorinated or unfluorinated derivatives thereof, and
tetracyanonaphthoquinodimethane and fluorinated or unfluorinated
derivatives thereof.
17. The optoelectronic component according to claim 14, wherein the
conductivity of the organic functional layer is greater than a sum
of a first conductivity, generated by sole interaction of the first
compound with the matrix material, and of a second conductivity,
generated by sole interaction of the second compound with the
matrix material.
18. The optoelectronic component according to claim 14, wherein at
least one coordinate bond is formed by the first compound with the
second compound and by the first compound with the matrix material
and/or by the second compound with the matrix material.
19. The optoelectronic component according to claim 14, wherein the
second compound comprises an electron acceptor in relation to the
matrix material and/or an electron donor in relation to the first
compound.
20. The optoelectronic component according to claim 14, wherein a
third compound is generated by complexing of first and second
compounds in the gas phase, the third compound produced by
simultaneous vaporization from different sources of the first
compound, of the second compound and of the matrix material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional application of U.S. application Ser.
No. 14/895,486, entitled "Optoelectronic Component, Organic
Functional Layer, and Method for Producing an Optoelectronic
Component," which was filed on Dec. 2, 2015, which is a national
phase filing under section 371 of PCT/EP2014/063410, filed Jun. 25,
2014, which claims the priority of German patent application 10
2013 106 949.5, filed Jul. 2, 2013, all of which is incorporated
herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to an optoelectronic
component, to an organic functional layer, and to a method for
producing an optoelectronic component.
SUMMARY
[0003] A problem frequently affecting components which emit
radiation, such as organic light-emitting diodes (OLEDs), for
example, is that of providing one or more layers having a high
conductivity of electrons and/or holes. A higher conductivity in
the layers, such as in hole transport or electron transport layers,
for example, often positively influences the exciton density in a
layer which emits radiation. In the event of inadequate
conductivity in the layers, in contrast, increased efficiency
losses and luminance losses in components that emit radiation may
be the consequence.
[0004] Embodiments of the invention specify an optoelectronic
component, an organic functional layer which can be used therein,
for example, and also a method for producing an optoelectronic
component, exhibiting improved conductivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0006] FIG. 1 shows the schematic side view of an optoelectronic
component;
[0007] FIG. 2 shows the concentration dependence of the specific
conductivity K of comparative examples and according to an
inventive embodiment;
[0008] FIG. 3 shows the measuring geometry of an organic test
structure; and
[0009] FIG. 4 shows the specific conductivity K by interaction of a
first compound and a second compound, according to a further
embodiment, in comparison to comparative examples.
[0010] In the working examples and figures, constituents which are
identical or of identical effect are each provided with the same
reference symbols. The elements shown and their size relationships
with one another should be considered in principle not to be true
to scale. Moreover, identical working examples of first and second
compounds and matrix material are given the same abbreviated
designations.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0011] In the text below, advantages and advantageous embodiments
and development of the subject matter of the invention will be in
more detail using figures and working examples.
[0012] An optoelectronic component according to one embodiment
comprises a substrate, a first electrode, a second electrode, and
at least one organic functional layer which is arranged between
first electrode and second electrode. The organic functional layer
comprises a matrix material, a first compound and a second
compound, the first compound interacting with the second compound,
and the first compound and/or the second compound interacting with
the matrix material. The interactions generate a conductivity in
the organic functional layer that is improved relative to the
conductivity of the matrix material alone.
[0013] The inventors have surprisingly determined that in the
operation of an optoelectronic component, a combination of matrix
material, first compound and second compound in at least one
organic functional layer brings about increased conductivity in the
organic functional layer. This results, furthermore, in an
increased luminance and recombination efficiency, and so leads to
an increased luminous efficiency of the optoelectronic component.
The electromagnetic radiation generated by charge carrier
recombination can in principle be outcoupled through the first or
second electrode or through both.
[0014] Electromagnetic radiation here and below preferably
comprises electromagnetic radiation having one or more wavelengths
or wavelength ranges from an ultraviolet to infrared spectral
range, the electromagnetic radiation more preferably being visible
light having wavelengths or wavelength ranges from a visible
spectral range between about 350 nm and about 800 nm.
[0015] In the context of this specification, the term "component"
comprehends not only completed components such as, for example,
organic light-emitting diodes (OLEDs) but also substrates and/or
organic layer sequences. An assembly of an organic layer sequence
with a first electrode and a second electrode may already
constitute a component, for example, and may form a constituent of
a superordinate second component, in which, for example, electrical
connections are additionally present.
[0016] "Arranged between first electrode and second electrode" does
not rule out the arrangement between the electrodes of further
layers or elements, although the functional organic layer is always
at least in indirect electrical and/or mechanical contact with one
of the electrodes.
[0017] "Conductivity" here and below refers to the capacity of at
least one substance to transport charge carriers--for example,
negative charge carriers (electrons) and/or positive charge
carriers (holes). The conductivity may be generated by interaction
of at least two or three substances, as for example, by interaction
of the first compound with the second compound, or of the first
compound and/or of the second compound with the matrix material.
The conductivity is dependent on the product of charge, charge
carrier concentration and mobility of the charge carriers.
[0018] According to one embodiment, the conductivity of the organic
functional layer is greater than a sum of a first conductivity,
generated by sole interaction of the first compound with the matrix
material, and of a second conductivity, generated by sole
interaction of the second compound with the matrix material. The
interaction of first and second compounds generates increased
particle transport, holes, for example, in the organic functional
layer, and an increased luminance and efficiency in the
optoelectronic component.
[0019] "Sole interaction" in this context means that first compound
and matrix material or second compound and matrix material interact
exclusively with one another. More particularly "sole interaction"
may mean that only first compound and matrix material or second
compound and matrix material are conductive.
[0020] The interaction of the first compound with the second
compound and/or of the first compound and/or of the second compound
with the matrix material means in this context that
between-molecule forces, intermolecular forces, intramolecular
forces and/or chemical bonds are formed between the first compound
and the second compound and/or between the first compound and/or
second compound and the matrix material, examples being ionic
interaction, hydrogen bonds, dipole interaction, Van der Waals
interaction, ionic bonding, covalent bonding, coordinate bonding
and/or metallic bonding.
[0021] In particular, at least one coordinate bond is formed by the
first compound with the second compound and by the first compound
with the matrix material and/or by the second compound with the
matrix material.
[0022] "Coordinate bond" here and below indicates that between an
electron donor and an electron acceptor a bond is formed, the
electron donor providing all the electrons required for the
formation of the coordinate bond, and the electron acceptor
accepting the electrons provided. In particular, the electron donor
and/or the electron acceptor may exchange electrons only partly or
to a slight extent.
[0023] According to one embodiment, the first compound is an
electron acceptor in relation to the matrix material and/or an
electron acceptor in relation to the second compound.
[0024] According to a further embodiment, the second compound is an
electron acceptor in relation to the matrix material and/or an
electron donor in relation to the first compound.
[0025] According to another embodiment, the second compound in
comparison to the first compound is more strongly
electron-accepting relative to the matrix material.
[0026] According to one embodiment, in addition to first and second
compounds, there may also be additional compounds--for example, one
to three additional compounds--embedded in the matrix material, and
being capable of interacting with the first compound, the second
compound, the matrix material and/or one another, by forming
coordinate bonds, for example. Alternatively or additionally the
matrix material may be a mixture of two or more different matrix
materials.
[0027] According to one embodiment, the optoelectronic component is
an organic electronic component and is formed, for example, as an
organic light-emitting diode (OLED). This OLED may have a first
electrode on the substrate, for example. Applied over the first
electrode there may be at least the organic functional layer, or a
plurality of functional layers comprising organic materials.
Applied over the organic functional layer or the plurality of
functional layers is a second electrode.
[0028] The organic functional layer here may be selected from a
group which comprises a layer that emits radiation, a hole
transport layer, a hole injection layer, and a hole blocking layer.
More particularly the organic functional layer is a hole transport
layer and/or hole injection layer.
[0029] Any further organic functional layer may be selected from a
group which comprises an electron injection layer, an electron
transport layer, a hole blocking layer, or a layer which emits
radiation. The layer which emits radiation may comprise a single
layer or a plurality of sublayers, examples being layers or
sublayers which emit in the green, red and/or blue spectral range
of electromagnetic radiation. Alternatively or additionally it is
possible for the electron injection layer, electron transport layer
and hole blocking layer to feature an individual layer or a
plurality of sublayers.
[0030] The layer which emits radiation may also have an active
region which is suitable for giving off electromagnetic radiation
in the operation of the organic electronic component.
[0031] According to one embodiment, the optoelectronic component
may additionally have an encapsulation.
[0032] Alternatively, according to one further embodiment, the
optoelectronic component is formed in the form of a transistor, a
field effect transistor, for example, or a solar cell or a
photodetector.
[0033] The substrate may comprise glass, quartz, polymeric films,
metal, metal foils, silicon wafers, or another suitable substrate
material. The OLED may also be designed as a "bottom emitter",
meaning that the electromagnetic radiation generated in the active
region is given off through the substrate. In that case the
substrate has transparency for at least part of the electromagnetic
radiation. Advantageously, the first electrode, which may be
designed as anode, may be transparent and/or comprise a material
which injects holes. The first electrode may have or consist of a
transparent conductive oxide, for example. Transparent conductive
oxides ("TCO", for short) are generally metal oxides, such as zinc
oxide, tin oxide, cadmium oxide, titanium oxide, indium oxide or
indium tin oxide (ITO), for example. The group of the TCOs includes
not only binary metal-oxygen compounds, such as ZnO, SnO.sub.2 or
In.sub.2O.sub.3, for example, but also ternary metal-oxygen
compounds, such as Zn.sub.2SnO.sub.4, CdSnO.sub.3, ZnSnO.sub.3,
MgIn.sub.2O.sub.4, GaInO.sub.3, Zn.sub.2In.sub.2O.sub.5 or
In.sub.4Sn.sub.3O.sub.12, for example, or mixtures of different
transparent conductive oxides. These TCOs do not necessarily
conform to a stoichiometric composition, and may also be p- or
n-doped.
[0034] The at least one organic functional layer may feature
organic polymers, organic oligomers, organic monomers, organic
small nonpolymeric molecules ("small molecules") or combinations
thereof.
[0035] The second electrode may be designed as cathode and may
therefore serve as a material which injects electrons. As cathode
material, among others, in particular aluminum, barium, indium,
silver, gold, magnesium, calcium or lithium, and also compounds,
combinations and alloys thereof, may prove advantageous.
Alternatively or additionally, the second electrode may also have
one of the abovementioned TCOs. Additionally or alternatively, the
second electrode may also be of transparent design and/or the first
electrode may be designed as cathode and the second electrode as
anode. This means in particular that the OLED may also be designed
as a "top emitter".
[0036] The first and/or the second electrode may each be of
extensive format. Consequently, in the case of an OLED, it may be
made possible for the electromagnetic radiation generated in the
active region to be given off extensively. "Extensive" here may
mean that the organic electronic component has an area of greater
than or equal to several mm.sup.2, preferably greater than or equal
to one cm.sup.2 and more preferably greater than or equal to one
dm.sup.2. Alternatively or additionally, the first and/or the
second electrode(s) may be of structured format at least in partial
regions. As a result, it may be made possible for the
electromagnetic radiation generated in the active region to be
given off in a structured way, in the form of pixels or pictograms,
for instance.
[0037] In accordance with one embodiment, in the production of the
functional layer by simultaneous vaporization of the first
compound, the second compound and the matrix material from
different sources, a third compound is generated by complexation of
first and second compounds in the gas phase or in the layer. In
particular, the first and second compounds are distributed
homogeneously in the matrix material. Alternatively it is possible
to establish a concentration gradient of first and second compounds
in the matrix material. The third compound in particular forms an
electron donor-electron acceptor complex. In addition, the third
compound generates higher conductivity in the organic functional
layer.
[0038] According to one embodiment, the first compound and/or the
second compound is/are present in excess in the matrix material. By
this means it is possible to exert process control as well over the
conductivity of the organic functional layer, through the
concentration of holes, for example.
[0039] According to a further embodiment, the matrix material is
present in excess by comparison with the first and/or second
compound(s), preferably, for example, in an excess of more than
75%, especially preferably in an excess of above 90%. The
conductivity is proportional to the mobility of the charge carriers
and to the number of charge carriers. On addition of a first
compound and/or second compound to the matrix material, there is
normally a fall in mobility. However, this is overcompensated by
the generation of charge carriers, and so ultimately the
conductivity rises by several orders of magnitude. The conductivity
can therefore be controlled via the ratio of the matrix material to
the first compound and/or second compound. Gradients horizontally
and vertically are possible in terms of process technology.
[0040] The interaction of the first compound with the second
compound leads to coordination of the two compounds with one
another. The organic functional layer therefore comprises a third
compound in the coordinated state, in other words involving
formation of at least one coordinate bond of first and second
compounds. In the organic functional layer there is a short-range
order. Short-range order means that the entire layer per se is not
crystalline, but that around the first compound, in its immediate
vicinity, the second compound is arranged according to a particular
pattern. The entire organic functional layer is therefore amorphous
per se, and therefore does not have any long-range order.
[0041] According to one embodiment, the first compound comprises a
metal complex having at least one central metal atom. The central
metal atom of the first compound may be selected from an element of
the Periodic System, as for example, from an element from
transition group I, transition group VI and main group V of the
Periodic System. The central metal atom is selected more
particularly from a group which comprises Cu, Cr, Mo, and Bi.
[0042] Alternatively or additionally there may be at least two
central metal atoms linked directly via a metal-metal bond and/or
indirectly to one another. "Indirectly" in this context means that
two metal atoms are bridged or linked to at least one semimetal
atom and/or nonmetal atom, O, N, P, C, Si or B, for example, and no
direct metal-metal bond is formed.
[0043] According to at least one embodiment, the first compound is
a copper complex. Present in the copper complex there may be at
least one copper cation in the II oxidation state.
[0044] According to at least one embodiment, the copper complex has
at least one ligand which comprises an aryloxy group and an iminium
group.
[0045] According to at least one embodiment, the aryloxy group and
the iminium group of the ligand is a salicylaldiminate group. A
salicylaldiminate group means a ligand which is formed from a
salicylaldehyde and an aromatic monoamine or diamine or an olefinic
monoamine or diamine. The ligand therefore comprises an amine-fused
salicylaldehyde group and is capable of complexing between aryloxy
group and the nitrogen of the iminium group, an azomethine group,
for example.
[0046] According to at least one embodiment, the copper complex has
one of the general formulae I or II:
##STR00001##
[0047] Formula (I) constitutes a cis isomer of the copper complex,
formula (II) a trans isomer. A copper complex of this kind
therefore comprises two ligands, coordinated or bonded with the
copper cation.
[0048] Definitions in the formulae (I) and (II) are as follows:
R.sub.1, R.sub.1', R.sub.2x and R.sub.2x' (wherein x is in each
case a, b, c or d) are selected independently of one another from a
group which comprises unbranched, branched, fused, cyclic,
unsubstituted and substituted alkyl radicals, substituted and
unsubstituted aromatics, and substituted and unsubstituted
heteroaromatics. Examples of such substituents are methyl groups,
ethyl groups, decahydronaphthyl groups, cyclohexyl groups and alkyl
radicals, which may be wholly or partly substituted and may have up
to 20 carbon atoms. These alkyl radicals may further contain ether
groups, such as ethoxy or methoxy groups, ester groups, amide
groups, carbonate groups or else halogens, especially F.
[0049] Examples of substituted or unsubstituted aromatics are
phenyl, biphenyl, naphthyl, phenanthryl or benzyl.
[0050] According to at least one embodiment, R.sub.1 and R.sub.1',
and R.sub.2x and R.sub.2x', are each identical.
[0051] According to at least one embodiment, R.sub.1 and R.sub.1'
are joined to one another.
[0052] According to at least one embodiment, at least one of
R.sub.1, R.sub.1', R.sub.2x and R.sub.2x' has an
electron-withdrawing substituent.
[0053] According to one embodiment, the first compound comprises at
least one ligand. The ligands are preferably coordinated and/or
bonded to at least one central metal atom of the first compound.
Ligands may be selected from a group as published in WO 2011/033023
A1 or US 2011/0089408 A1, or DE 102010013495 A1 or WO 2011/120709
A1. An example of a suitable ligand is pentafluorobenzoate,
fluorinated acetate or fluorinated acetylacetonate. A first
compound may be, for example, fluorinated copper(I) acetate,
fluorinated copper acetylacetonate or copper(II)
trifluoromethanesulfonate.
[0054] The ligand of the first compound may be selected more
particularly from the following group and combinations thereof:
[0055] fluorinated or nonfluorinated benzoic acids such as, for
example, 2-(trifluoromethyl)benzoic acid; 3,5-difluorobenzoic acid;
3-hydroxy-2,4,6-triiodobenzoic acid; 3-fluoro-4-methylbenzoic acid;
3-(trifluoromethoxy)benzoic acid; 4-(trifluoromethoxy)benzoic acid;
4-chloro-2,5-difluorobenzoic acid; 2-chloro-4,5-difluorobenzoic
acid; 2,4,5-trifluorobenzoic acid; 2-fluorobenzoic acid;
4-fluorobenzoic acid; 2,3,4-trifluorobenzoic acid;
2,3,5-trifluorobenzoic acid; 2,3-difluorobenzoic acid;
2,4-bis(trifluoromethyl)benzoic acid; 2,4-difluorobenzoic acid;
2,5-difluorobenzoic acid; 2,6-bis(trifluoromethyl)benzoic acid;
2,6-difluorobenzoic acid; 2-chloro-6-fluorobenzoic acid;
2-fluoro-4-(trifluoromethyl)benzoic acid;
2-fluoro-5-(trifluoromethyl)benzoic acid;
2-fluoro-6-(trifluoromethyl)benzoic acid; 3,4,5-trifluorobenzoic
acid; 3,4-difluorobenzoic acid; 3,5-bis(trifluoromethyl)benzoic
acid; 3-(trifluoro-methyl)benzoic acid; 3-chloro-4-fluorobenzoic
acid; 3-fluoro-5-(trifluoromethyl)benzoic acid; 3-fluorobenzoic
acid; 4-fluoro-2-(trifluoromethyl)benzoic acid;
4-fluoro-3-(trifluoromethyl)benzoic acid; 5-fluoro-2-methylbenzoic
acid; 2-(trifluoromethoxy)benzoic acid; 2,3,5-trichlorobenzoic
acid; 4-(trifluoromethyl)benzoic acid; pentafluorobenzoic acid;
2,3,4,5-tetrafluorobenzoic acid;
[0056] fluorinated or nonfluorinated phenylacetic acid such as, for
example, 2-fluorophenylacetic acid; 3-fluorophenylacetic acid;
4-fluorophenylacetic acid; 2,3-difluorophenylacetic acid;
2,4-difluorophenylacetic acid; 2,6-difluorophenylacetic acid;
3,4-difluorophenylacetic acid; 3,5-difluorophenylacetic acid;
pentafluorophenylacetic acid; 2-chloro-6-fluorophenylacetic acid;
2-chloro-3,6-difluorophenylacetic acid;
3-chloro-2,6-difluorophenylacetic acid;
3-chloro-4-fluorophenylacetic acid; 5-chloro-2-fluorophenylacetic
acid; 2,3,4-trifluorophenylacetic acid; 2,3,5-trifluorophenylacetic
acid; 2,3,6-trifluorophenylacetic acid; 2,4,5-trifluorophenylacetic
acid; 2,4,6-trifluorophenylacetic acid; 3,4,5-trifluorophenylacetic
acid; 3-chloro-2-fluorophenylacetic acid;
.alpha.-fluorophenylacetic acid; 4-chloro-2-fluorophenylacetic
acid; 2-chloro-4-fluorophenylacetic acid;
.alpha.,.alpha.-difluorophenylacetic acid; ethyl
2,2-difluoro-2-phenylacetate; and
[0057] fluorinated or nonfluorinated acetic acid such as, for
example, methyl trifluoroacetate; allyl trifluoroacetate; ethyl
trifluoroacetate; isopropyl trifluoroacetate; 2,2,2-trifluoroethyl
trifluoroacetate; difluoroacetic acid; trifluoroacetic acid; methyl
chlorodifluoroacetate; ethyl bromodifluoroacetate;
chlorodifluoroacetic acid; ethyl chlorofluoroacetate; ethyl
difluoroacetate; (3-chlorophenyl)difluoroacetic acid;
(3,5-difluoro-phenyl)difluoroacetic acid;
(4-butylphenyl)difluoroacetic acid;
(4-tert-butylphenyl)difluoroacetic acid;
(3,4-dimethylphenyl)difluoroacetic acid;
(3-chloro-4-fluorophenyl)difluoroacetic acid;
(4-chlorophenyl)difluoroacetic acid;
2-biphenyl-3',5'-difluoroacetic acid;
3-biphenyl-3',5'-difluoroacetic acid;
4-biphenyl-3',5'-difluoroacetic acid;
2-biphenyl-3',4'-difluoroacetic acid;
3-biphenyl-3',4'-difluoroacetic acid;
4-biphenyl-3',4'-difluoroacetic acid; 2,2-difluoropropionic acid
and/or higher homologs thereof. If the ligands L have acidic
groups, the groups, in one preferred embodiment, may be in
deprotonated form.
[0058] In at least one further embodiment, the ligand is selected
from the group of unsubstituted, partially fluorinated or
perfluorinated organic carboxylic acids. Organic carboxylic acids
may generally be selected from the groups of aliphatically,
saturated monocarboxylic acids; aliphatically, unsaturated
monocarboxylic acids; aliphatically, saturated dicarboxylic acids;
aliphatically, saturated tricarboxylic acids; aliphatically,
unsaturated dicarboxylic acids; aromatic carboxylic acids;
heterocyclic carboxylic acids; aliphatically, unsaturated, cyclic
monocarboxylic acids. Particularly preferred partial or
perfluorinated ligands L are selected from substituted or
unsubstituted compounds of acetic acid, phenylacetic acid and/or
benzoic acid and are given by way of example above. Particularly
preferred is unfluorinated, partially fluorinated or perfluorinated
acetic acid.
[0059] According to at least one embodiment, at least one of the
ligands is arranged in bridging form between two metals.
[0060] In one embodiment, a first compound has Bi as central metal
atom, but this atom is not coordinated with a bridging ligand.
[0061] According to one embodiment, the first compound, as for
example, the central metal atom and/or the ligand of the first
compound, comprises at least one coordination site.
[0062] According to one embodiment, the first compound, as for
example, the central metal atom of the first compound, comprises at
least one free coordination site, which is capable of accepting an
electron pair of a second substance, as for example, the second
compound, and forming a coordinate bond. This may also be referred
to as Lewis acid-Lewis base interaction.
[0063] "Coordination site" here and below denotes at least one
binding site. The coordination sites of the first compound may
interact with the second compound and/or with the matrix material.
Free coordination sites of the first compound may mean that there
are empty orbitals of the central metal atom or of the central
metal atoms, such as d-orbitals, p-orbitals or f-orbitals, for
example, which are occupied in the course of interactions with
electron pairs of the second compound and/or with the matrix
material. As a result of the overlapping of the orbitals, an
electron donor-electron acceptor complex may be generated, in which
case holes (defect electrons) migrate. In the case of hole
transport, an electron from a HOMO (Highest Occupied Molecular
Orbital) fills a hole. The holes are transported via the matrix
material, since there are percolation pathways here. The electron
acceptor withdraws an electron entirely or partly from the matrix
material and therefore generates a hole in the matrix material.
This hole then migrates according to the process above. This
increases the hole conductivity, the efficiency, and the lifetime
of the optoelectronic component.
[0064] Additionally or alternatively, the coordination sites may be
easily accessible and are not shielded by ligands.
[0065] According to one embodiment the first compound comprises a
structural unit 1
##STR00002##
[0066] and/or a structural unit 2
##STR00003##
[0067] wherein Cu in the structural unit 1 does not necessarily
mean only copper, Cu instead standing for a complexed metal which
is selected from a group which comprises copper, chromium,
molybdenum and bismuth, and combinations thereof, and Cr in the
structural unit 2 does not necessarily mean only chromium, Cr
instead standing for a complexed metal which is selected from a
group which comprises copper, chromium, molybdenum and bismuth, and
combinations thereof. In particular, Cr stands for a divalent
bismuth.
[0068] R.sub.1, R.sub.2, R.sub.3 and/or R.sub.4 are identical or
nonidentical and are each selected from a group which comprises
substituted or unsubstituted hydrocarbon radicals, alkyl radicals,
cycloalkyl radicals, heterocycloalkyl radicals, aryl radicals,
heteroaryl radicals, and combinations thereof. The hydrocarbon
radicals or alkyl radicals may be branched, linear or cyclic. The
aryl and/or heteroaryl radicals may have one ring or a plurality of
rings. The rings may be fused. A "ring" in this context means a
cyclic association of atoms which are selected, for example, from a
group comprising C, S, N, Si, O, P, and combinations thereof.
"Fused" rings in this context means that a plurality of rings have
at least one shared atom. Accordingly, even a spiro compound whose
rings are joined only at one atom may be referred to as fused. In
particular, at least two rings share two atoms with one
another.
[0069] According to at least one embodiment, central metal atoms
which comprise Cr and/or Mo form a dimeric first compound. Cu as
central metal atom forms a tetrameric, hexameric, etc. first
compound. In particular, trivalent Bi as central metal atom does
not form a first compound according to structural unit 2.
[0070] In particular, 2 to 6 rings, more particularly 4 rings, are
fused. Alternatively or additionally, the ring or the plurality of
rings may have a conjugation. "Conjugation" in this context means
that the ring or the plurality of rings has single and double bonds
in alternation.
[0071] The arrows in the structural units 1 or 2 show possible
coordination sites on the central metal atoms of the first
compound.
[0072] The structural unit 1 has at least four free coordination
sites. The structural unit 2 has at least two coordination
sites.
[0073] Branched, linear or cyclic hydrocarbon radicals may
comprise, in particular, 1-20 carbon atoms, examples being methyl,
ethyl or fused rings, such as decahydronaphthyl or adamantyl,
cyclohexyl, or wholly or partly substituted alkyl radicals.
Alternatively or additionally, R.sub.1, R.sub.2, R.sub.3 and/or
R.sub.4 may comprise substituted or unsubstituted aryl radicals,
examples being phenyl, biphenyl, naphthyl, phenanthryl, benzyl,
mesityl or heteroaryl radicals, examples being substituted or
unsubstituted radicals selected from the following aromatic parent
structures (scheme 1):
##STR00004## ##STR00005##
[0074] According to one embodiment, the first compound is
tetrakis-Cu(I) perfluorobenzoate, referred to here and below by the
abbreviated designation Cu(I)pFBz, or dichromium(II)
tetrakistrifluoroacetate. In principle, however, further compounds
known per se may also be used as first compound.
[0075] According to one embodiment, the first compound may be
selected from a group which comprises copper(I) complexes as
described, for example, in US 2011/0 089 408 A1, copper(II)
complexes as described, for example, in US 2011/0 089 408 A1,
copper(II) acetylacetonate as described, for example in DE 10 2010
013 495 A1, metal complexes, such as rhodium trifluoroacetate, for
example, as described, for example, in DE 10 2007 028 237 A1 and DE
10 2007 028 238 A1.
[0076] The above-described embodiments of the first compound differ
here in their electron acceptor strength in relation to the matrix
material and relative to an identical concentration of the first
compound in the matrix material. The first compound is in
particular a copper(I) complex as described, for example, in US
2011/0 089 408 A1, and a rhodium complex, such as rhodium
trifluoroacetate, for example, as described, for example, in DE 10
2007 028 237 A1 and DE 10 2007 028 238 A1. This confers a positive
influence on the appearance of the optoelectronic component in the
switched-off state.
[0077] According to one embodiment, the second compound comprises
an aromatic and/or heteroaromatic which has at least two functional
groups which are capable of forming a coordinate bond and/or of
.pi.-.pi. interaction.
[0078] The .pi.-.pi. interaction may be developed in particular
between aromatics with different acceptor strengths of first,
second and/or the matrix material.
[0079] .pi.-.pi. interactions are forces which occur between
.pi.-systems of molecules, examples being .pi.-systems of
unsaturated compounds, and which come about as a result of their
quadrupole moments.
[0080] The aromatics and/or heteroaromatics in particular have a
ring or a plurality of rings. The aromatics and/or heteroaromatics
may in particular comprise 2 to 6 rings, more particularly 4 rings.
Alternatively or additionally, the ring or the plurality of rings
is fused.
[0081] The functional groups are selected more particularly from a
group which comprises amine, phosphine, phenol, thiol, cyano,
isocyano, cyanato, nitrato, carboxylato, fluorinated carboxylato,
acetylacetonate, fluorinated acetylacetonate, carbonyl, amide,
imide, thienyl, fluoro, and combinations thereof.
[0082] The functional groups may also be electron donors.
[0083] According to one embodiment, the functional groups are
capable of forming coordinate bonds which are developed to the
first compound and/or to the matrix material.
[0084] According to one embodiment, the second compound has
hole-conducting properties. The second compound may conduct holes
or positive charges. As a result of this, the conductivity of the
organic functional layer may be increased. This results in a lower
voltage drop in the organic functional layer and hence in a higher
efficiency of the optoelectronic component in comparison to an
organic functional layer having a lower conductivity and a greater
voltage drop, provided the charge carrier equilibrium remains
constant. An additional effect of this is a higher exciton density
in the layer which emits radiation, and hence a higher luminous
efficiency of the optoelectronic component.
[0085] According to one embodiment, the second compound comprises
at least one heteroaromatic which comprises at least one of the
aromatic parent structures from scheme 1. In particular, the
functional groups are linked to at least one aromatic parent
structure from scheme 1.
[0086] The second compound may additionally have a conjugation; for
example, the second compound has alternating single and double
bonds.
[0087] According to one embodiment, the second compound comprises a
structural unit 3
##STR00006##
[0088] and/or a structural unit 4
##STR00007##
[0089] wherein F1, F2, F3, F4, F5, F6, F7, F8, F9 and/or F10 may be
identical or nonidentical, are independent of one another, and are
selected from a group which comprises amine, phosphine, phenol,
thiol, cyano, isocyano, cyanato, nitrato, carboxylato, carbonyl,
amide, imide, tienyl, fluoro, and combinations thereof. Cyanato is
preferred in particular.
[0090] Alternatively or additionally, the structural units 3 or 4
may be substituted on the C atoms. Substituents may be selected
from a group which comprises alkyl, aryl, heteroaryl, cycloalkyl,
fluoro.
[0091] The second compound is selected more particularly from a
group which comprises
dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile
(used here with the abbreviated designation HAT-CN),
7,7,8,8-tetracyanoquionodimethane (used here with the abbreviated
designation TCQ),
2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (used here
with the abbreviated designation FCQ),
2,3-di(N-phthalimido)-5,6-dicyano-1,4-benzoquinone (used here with
the abbreviated designation PBQ),
pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile and the
fluorinated or unfluorinated derivatives thereof, and
tetracyanonaphthoquinodimethane and the fluorinated or
unfluorinated derivatives thereof. The formulae of HAT-CN, TCQ, FCQ
and PBQ are shown below. The arrows on the formulae show possible
coordination sites which are capable of coordinating, for example,
to the first compound and/or to the matrix material.
##STR00008##
[0092] According to one embodiment, the second compound has a
.pi.-electron system which comprises at least one ring, as for
example, 1 to 6 rings. As a result, electrons of the first compound
and/or second compound and/or holes may be localized in the matrix
material. This results in a higher conductivity of the organic
functional layer and therefore leads to a higher luminous
efficiency of the optoelectronic component.
[0093] In one embodiment of the optoelectronic component, the metal
complex of the first compound coordinates to one of the functional
groups or to a plurality of the functional groups of the second
compound. The coordination of the second compound to the central
metal atom of the first compound may be via the functional groups
of the second compound or via an atom, N, P, S or O for example, in
the aromatic system of the second compound. During or after the
coordination of the first compound to the second compound, there is
preferably no elimination of the metal complex ligands treated
beforehand, and therefore there is no ligand exchange.
[0094] According to one embodiment, the first compound forms a
plurality of coordinate bonds with the second compound in such a
way as to produce a chainlike structure and/or a netlike
structure.
[0095] It is also possible for additional compounds to be
incorporated into the matrix material, these compounds forming a
chainlike and/or netlike structure--a three-dimensional structure,
for example--by interaction with the first compound, the second
compound and/or the matrix material.
[0096] According to one embodiment, the first compound, as well as
having a "central metal atom" structural element M, has at least
one "free coordination site" structural element KS.sub.n (index n
here denotes the number of coordination sites). The second compound
has an "aromatics and/or heteroaromatics" structural element A and
at least one "functional group" structural element FG.sub.m (index
m here denotes the number of functional groups). A "structural
element" in this context refers to a characteristic region of the
structural formula. For example, the "functional group" structural
element FG.sub.n comprises all above-treated functional groups of
the second compound. The "central metal atom" structural element M
comprises the above-treated central metal atoms of the first
compound. The "free coordination site" structural element KS.sub.n
comprises the above-treated free coordination sites of the first
compound. The "aromatics and/or heteroaromatics" structural element
A comprises the above-treated aromatics and/or heteroaromatics of
the second compound. At least one "free coordination site"
structural element, for example, KS.sub.1, is capable of
interacting with the "functional group" structural element, for
example, FG.sub.1 of the second compound. This may be generated,
for example, by formation of at least one coordinate bond. As a
result it is possible for a chainlike structure and/or a netlike
structure to form (see schematic diagram below).
##STR00009##
[0097] Here and in this context:
[0098] M: denotes a "central metal atom" structural element of the
first compound
[0099] KS.sub.n: denotes an "nth free coordination site" structural
element of the first compound,
[0100] KS.sub.1: denotes a "first free coordination site"
structural element of the first compound,
[0101] KS.sub.2: denotes a "second free coordination site"
structural element of the first compound,
[0102] A: denotes an "aromatics and/or heteroaromatics" structural
element of the second compound,
[0103] FG.sub.m: denotes an "mth functional group" structural
element of the second compound,
[0104] FG.sub.1: denotes a "first functional group" structural
element of the second compound,
[0105] FG.sub.2: denotes a "second functional group" structural
element of the second compound, and
[0106] W: denotes interactions between "first free coordination
site" structural element of the first compound and "first
functional group" structural element of the second compound.
[0107] According to one embodiment, the first compound and/or
second compound may be used as a p-dopant. "p-Dopant" in this
context means that the dopant is capable of receiving electrons of
the matrix material and so generating holes in the matrix
material.
[0108] According to one embodiment, the organic functional layer is
a hole transport layer. The addition of a first compound to a
second compound in a matrix material of the hole transport layer
results in an improved hole transport capacity as compared with the
matrix material which comprises no first and second compounds. This
improved hole transport can be explained by the transfer of the
holes or of the positive charge of the molecules of the matrix
material that are able to interact with the first or second
compound.
[0109] The following are shown below by way of example:
[0110] scheme 2: interaction of the first compound, exemplified by
Cu(I)pFBz, with the second compound, exemplified by HAT-CN;
[0111] scheme 3: interaction of the first compound, exemplified by
Cu(I)pFBz, with the second compound, exemplified by HAT-CN, and
interaction of the first compound, exemplified by Cu(I)pFBz, with
the matrix material, exemplified by
N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidene (NPD); and
[0112] scheme 4: interaction of the first compound, exemplified by
Cu(I)pFBz, with the second compound, exemplified by HAT-CN, and
interaction of the second compound, exemplified by HAT-CN, with the
matrix material, exemplified by NPD. The interactions are not
limited to the interactions shown in schemes 1 to 4 or other
interactions of compounds described in the working examples.
Instead, another working example of the first compound, second
compound and/or matrix material may also be utilized. In addition
it is possible for first compound, second compound and/or matrix
material to interact via at least one .pi.-.pi. interaction between
two aromatics with different acceptor strengths, as is shown, for
example, in DE 10 2007 028 238 A1 and/or in Sevryugina et al.,
Inorg. Chem. 2007, 46, 7870-7879.
##STR00010##
##STR00011##
[0113] According to one embodiment, not all molecules of the matrix
material interact with the molecules of the first compound and/or
second compound.
[0114] The matrix material, the hole transport layer, for example,
may be selected from a group which comprises one or more compounds
of the following groups: NPB
(N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine, .beta.-NPB
(N,N'-bis(naphthalen-2-yl)-N,N'-bis(phenyl)benzidine), TPD
(N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine),
N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-2,2-dimethylbenzidine,
spiro-TPD
(N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-9,9-spirobifluorene)- ,
spiro-NPB
(N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-9,9-spirobifluorene),
DMFL-TPD
(N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-9,9-dimethylfluorene,
DMFL-NPB
(N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-9,9-dimethylfluorene-
), DPFL-TPD
(N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-9,9-diphenylfluorene),
DPFL-NPB
(N,N'-bis(naphth-1-yl)-N,N'-bis(phenyl)-9,9-diphenylfluorene),
Sp-TAD
(2,2',7,7'-tetrakis(n,n-diphenylamino)-9,9'-spirobifluorene), TAPC
(di[4-(N,N-ditolylamino)phenyl]cyclohexane), spiro-TTB
(2,2',7,7'-tetra(N,N-ditolyl)aminospirobifluorene), BPAPF
(9,9-bis[4-(N,N-bisphenyl-4-yl-amino)phenyl]-9H-fluorene),
spiro-2NPB
(2,2',7,7'-tetrakis[N-naphthyl(phenyl)amino]-9,9-spirobifluorene),
spiro-5
(2,7-bis[N,N-bis(9,9-spirobifluoren-2-yl)amino]-9,9-spirobifluore-
ne), 2,2'-spiro-DBP
(2,2'-bis[N,N-bis(biphenyl-4-yl)amino]-9,9-spirobifluorene), PAPB
(N,N'-bis(phenanthren-9-yl)-N,N'-bis(phenyl)benzidine), TNB
(N,N,N',N'-tetranaphthalen-2-yl-benzidine), spiro-BPA
(2,2'-bis(N,N-diphenylamino)-9,9-spirobifluorene), NPAPF
(9,9-bis[4-(N,N-bisnaphth-2-yl-amino)phenyl]-9H-fluorene), NPBAPF
(9,9-bis[4-(N,N'-bisnaphth-2-yl-N,N'-bisphenylamino)phenyl]-9H-fluorene),
TiOPC (titanium oxide phthalocyanine), CuPC (copper
phthalocyanine), F4-TCNQ
(2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), m-MTDATA
(4,4',4''-tris(N-3-methylphenyl-N-phenylamino)triphenylamine),
2T-NATA
(4,4',4''-tris(N-(naphthalen-2-yl)-N-phenylamino)triphenylamine),
1T-NATA
(4,4',4''-tris(N-(naphthalen-1-yl)-N-phenylamino)triphenylamine),
NATA (4,4',4''-tris(N,N-diphenylamino)triphenylamine), PPDN
(pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile), MeO-TPD
(N,N,N',N'-tetrakis (4-methoxy-phenyl)benzidine), MeO-spiro-TPD
(2,7-bis[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene),
2,2'-MeO-spiro-TPD
(2,2'-bis[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene),
.beta.-NPP
(N,N'-di(naphthalen-2-yl)-N,N'-diphenylbenzene-1,4-diamine), NTNPB
(N,N'-diphenyl-N,N'-di-[4-(N,N-ditolylamino)phenyl]benzidine and
NPNPB
(N,N'-diphenyl-N,N'-di-[4-(N,N-diphenylamino)phenyl]benzidine). The
listing is by no means limited, however. Any matrix material which
commonly transports holes is suitable as a constituent of the
organic functional layer.
[0115] According to one embodiment, the fraction of the matrix
material in the organic functional layer is more than 50%,
preferably more than 80%, and more preferably more than 90%, as for
example, 95%.
[0116] In a further embodiment, the organic functional layer is an
electron-blocking layer.
[0117] Further specified is an organic functional layer which
comprises a matrix material, a first compound, and a second
compound, the first compound forming an electron donor-electron
acceptor complex with the second compound via at least one
coordinate bond, and the first compound and/or the second compound
interacting, as electron acceptor, with the matrix material, and
the interaction in the electron donor-electron acceptor complex
generating conductivity in the organic functional layer.
[0118] For the organic functional layer, the matrix material, the
first compound and/or the second compound, the definitions and
observations which apply are the same as those specified above in
the description for an optoelectronic component.
[0119] According to one embodiment, the conductivity of the organic
functional layer is greater than a sum of a first conductivity,
generated by sole interaction of the first compound with the matrix
material, and of a second conductivity, generated by sole
interaction of the second compound with the matrix material.
[0120] According to one embodiment, the organic functional layer is
a constituent of an organic light-emitting diode, of a transistor,
a field effect transistor, for example, of a solar cell or of a
photodetector.
[0121] Further specified is a method for producing an
optoelectronic component, the method comprising the following
steps:
[0122] A) providing a substrate,
[0123] B) applying a first electrode,
[0124] C) depositing at least one organic functional layer or a
plurality of organic functional layers on the substrate,
[0125] D) applying a second electrode,
[0126] the depositing of the organic functional layer taking place
by simultaneous vaporization from different sources of a first
compound, of a second compound, and of a matrix material.
[0127] The deposition of the organic functional layer by
simultaneous vaporization from different sources of a first
compound, of a second compound, and of a matrix material causes a
higher conductivity on the part of the organic functional layer.
Particularly when using an organic functional layer having a
thickness of 5 nm to 600 nm, preferably 100 to 400 nm, to reduce
the susceptibility to an electrical short-circuit in the
optoelectronic component, in extensive OLEDs, for example, the
vertical voltage drop across the organic functional layer can be
reduced further, thereby boosting efficiency, including luminous
efficiency, of the optoelectronic component. Additionally, the
lateral current distribution of the optoelectronic component can be
improved if the conductivity of the organic functional layer is in
the order of magnitude of conductivity of the first electrode
and/or second electrode, such as of indium tin oxide, i.e., tin
oxide-doped indium oxide (no), for example.
[0128] Alternatively or additionally, in method step D, at least
the first and second compounds may be mixed prior to vaporization,
with the depositing of the organic functional layer taking place by
simultaneous vaporization from a source of the first and second
compounds and from another source of the matrix material.
[0129] For the method for producing an optoelectronic component,
the definitions and observations which apply are the same as those
specified above in the description for an optoelectronic
component.
[0130] According to one embodiment, the number of coordinate bonds
between the first organic compound and the second organic compound
and/or between the first organic compound and the matrix material
and/or between the second organic compound and the matrix material
may be controlled by concentration change during vaporization.
[0131] FIG. 1 shows a schematic side view of an optoelectronic
component, using the working example of an organic light-emitting
diode (OLED). The OLED comprises a substrate 1, which is located
right at the bottom and may be, for example, transparent and may be
made of glass. Arranged on the substrate 1 is a first electrode 2,
which may be formed as a layer, and may be, for example, a
transparent conductive oxide such as, for example, zinc oxide, tin
oxide, cadmium oxide, titanium oxide, indium oxide or indium tin
oxide (ITO). Located above this electrode layer 2 is a hole
injection layer 3, arranged above which in turn is the hole
transport layer 4. Located thereon is a layer which emits radiation
and which may have, for example, a plurality of individual layers.
On the layer 5 which emits radiation there is the hole-blocking
layer 6, on which the electron transport layer 7 and, lastly, the
electron injection layer 8, with adjacent second electrode 9, may
be arranged. The second electrode 9 may be, for example, a metal
electrode or a further transparent electrode, made from one of the
aforementioned transparent conductive oxides, for example. The
organic functional layer of the invention is, for example, the hole
injection layer, hole transport layer, hole blocking layer, or
layer which emits radiation.
[0132] If a voltage is applied between the first electrode 2 and
the second electrode 9, current flows through the optoelectronic
component. In that case, one electrode, the cathode, injects
electrons into the electron injection layer 8, and the other
electrode, the anode, injects what are called holes. In the layer 5
which emits radiation, the holes and electrons recombine, forming
electron-hole pairs, known as excitons, which are capable of
emitting electromagnetic radiation.
[0133] Alternatively, an optoelectronic component (not shown here)
is formed as an OLED with substrate 1, first electrode 2, organic
functional layer and second electrode 9.
[0134] An alternative possibility is an arrangement of an
optoelectronic component (not shown here) in the form of an OLED
composed of substrate 1, first electrode 2, hole injection layer 3,
electron transport layer 5, and second electrode 9.
[0135] Alternatively or additionally, the first and second
compounds in the matrix material are formed as a film or as a
casting, and are arranged or applied to or over the first electrode
(not shown here).
[0136] Alternatively it is possible to form the hole injection
layer 3, the hole transport layer 4 or the layer 5 which emits
radiation as an organic functional layer, with the organic
functional layer comprising the first compound and second compound
in a matrix material.
[0137] The organic functional layer in accordance with the present
invention here may be any layer in which holes are transported. The
organic functional layer in accordance with the invention
preferably comprises the hole injection layer 3 or hole transport
layer 4. The organic functional layer may also, however, be the
layer 5 which emits radiation, for example, in such a way, for
example, that a further material, emitting radiation, is vaporized
with the first compound and with the second compound.
Alternatively, however, the material which emits radiation may also
be incorporated otherwise into the layer 5 which emits radiation.
As a result of the improved hole transport capacity, a greater
number of holes and electrons are able to recombine, thus forming
more excitons (electron-hole pairs). This results in an increase in
the exciton density in the layer 5 which emits radiation, thereby
increasing the luminance and efficiency of the optoelectronic
component.
[0138] Here and below, the following abbreviated designations are
used for comparative examples of first compound or second compound
in the matrix material:
[0139] V1: comparative example of a first compound Cu(I)pFBz in the
matrix material HTM-014 by Merck
[0140] V8: comparative example of a second compound HAT-CN in the
matrix material HTM-014, and
[0141] A1: working example of a first compound Cu(I)pFBz with a
solid fraction of 5% and a second compound HAT-CN with a variable
fraction in the matrix material HTM-014.
[0142] FIG. 2 shows the specific conductivity K in siemens per
meter (S.times.m.sup.-1) of comparative examples V1 and V8, and
also of working example A1, as a function of the concentration c,
expressed as a volume percentage, of the first compound Cu(I)pFBz
or of the second compound HAT-CN. In this case, an organic test
structure was used for the conductivity measurement in accordance
with FIG. 3. In FIG. 3, d denotes thickness of the organic test
structure, L length of the organic test structure, S width of the
organic test structure, K1 first contact, and K2 second contact.
Applied between the contacts K1 and K2 is a voltage, thereby
forming a homogeneous electrical field F in the semiconductor. The
specific conductivity K then results according to the following
equation:
K = j F = j S U = I S U L d ##EQU00001##
wherein j is current density and U is voltage.
[0143] By simultaneous thermal vaporization from different sources,
the respective matrix material, the first compound and the second
compound were deposited, as an organic functional layer with an
overall thickness of 120 nm, on an ITO (indium tin oxide=tin
oxide-doped indium oxide) electrode. The specific conductivity K
was calculated from the current-voltage characteristic curve, and
has been represented graphically in FIG. 2 and FIG. 4.
[0144] The matrix material exhibits a relatively poor specific
conductivity, K, of less than 10.sup.-6 S.times.m.sup.-1 (not shown
here). By vaporization of the first compound or second compound in
the matrix material, however, it is possible to achieve a specific
conductivity K of significantly greater than 10.sup.-6
S.times.m.sup.-1. The first compound Cu(I)pFBz in the matrix
material HTM-014 (V1) generates a higher specific conductivity K
than the second compound HAT-CN in the matrix material HTM-014
(V8). For an identical concentration, the specific conductivity K
for comparative example V1, for Cu(I)pFBz in HTM-014, is higher by
two orders of magnitude in comparison to V8, comprising HAT-CN in
HTM-014. With increasing concentration of the first compound
Cu(I)pFBz or second compound HAT-CN, an increase is observed in the
specific conductivity K. This results from interactions of the
first compound Cu(I)pFBz or second compound HAT-CN with the
respective matrix material. As a result, a high hole mobility and
charge transfer are made possible, and the luminous efficiency of
the optoelectronic component is improved.
[0145] Here and below, the following abbreviated designations are
used for working examples and comparative examples of first
compound and/or second compound in the matrix material:
[0146] V9: comparative example of a second compound HAT-CN with a
fraction of 10% in the matrix material HTM-014,
[0147] V10: comparative example of a first compound Cu(I)pFBz with
a fraction of 5% in the matrix material HTM-014,
[0148] A1: working example of a first compound Cu(I)pFBz with a
fraction of 5% and of a second compound HAT-CN with a fraction of
10% in the matrix material HTM-014, and
[0149] V11: comparative example of a first compound Cu(I)pFBz with
a fraction of 5% in the matrix material HTM-014. "Fraction" in this
context denotes the volume percent of the first compound or of the
second compound relative to the matrix material.
[0150] FIG. 4 shows the specific conductivity K in siemens per
meter (S.times.m.sup.-1) of V9, V10, A1 and V11. The specific
conductivity K of V9 is in the order of magnitude of 10.sup.-5 S/m,
whereas the specific conductivity K of V10 and V11 is higher by one
order of magnitude (K=10.sup.-4 S/m). Surprisingly, the specific
conductivity K of A1 is increased further by almost one order of
magnitude (approximately 10.sup.-3 S/m). The specific conductivity
K of the organic functional layer is increased significantly by the
addition of the first compound and of the second compound in the
matrix material, in contrast to the specific conductivity K, which
is generated by sole interaction of the first compound with the
matrix material (V10 or V11), and to the specific conductivity K
which is generated by sole interaction of the second compound with
the matrix material (V9). The specific conductivity K of A1 comes
about through an advantageous network of the first compound
Cu(I)pFBz and of the second compound HAT-CN in the matrix material
HTM-014. In the case of the vaporization of Cu(I)pFBz and HAT-CN,
there is no cross-contamination of materials in the sources. This
is shown in FIG. 4 by the virtually identical specific
conductivities K of V10 and V11, which were produced before and
after A1, respectively.
Synthesis of Copper(I) Pentafluorobenzoate
[0151] Cu.sub.2O (0.451 g, 3.15 mmol) is admixed with 2 ml of
(CF.sub.3CO).sub.2O, followed by 30 ml of benzene. The mixture is
heated under reflux overnight, giving a blue solution and a little
unreacted starting material. This suspension is filtered using
Celiter, in order to remove Cu.sub.2O. The blue solution is then
evaporated to dryness, giving a very pale blue solid. The desired
product is obtained by operating under reduced pressure at
60.degree. C. to 70.degree. C. for ten to 15 hours. The yield is
64%. The crystalline material can be obtained by sublimation of the
crude solid at 110.degree. C. to 120.degree. C.
[0152] The reaction product (0.797 g, 1.1 mmol) is kept with
pentafluorinated benzoic acid (0.945 g, 6.76 mmol) in a Schlenk
flask in a glovebox, with 55 ml of benzene being added to the
mixture. A homogeneous light-blue solution is heated under reflux
overnight and then evaporated to dryness, giving a pale blue solid.
Operation takes place under reduced pressure at 90.degree. C. to
100.degree. C. for several days, in order to remove the excess of
unreacted benzoic acid. A colorless solid stable in air is obtained
by sublimation deposition of the crude powder at 220.degree. C.
after a week. The yield of copper(I) pentafluorobenzoate is
65%.
[0153] Production of the Organic Functional Layer
[0154] The first compound (for example, Cu(I)pFBz), second compound
(for example, HAT-CN) and the matrix material (for example,
HMT-014), each in different sources, are heated thermally to their
respective sublimation points, and these compounds are vaporized
simultaneously. In this operation, the first compound, the second
compound and the matrix material are applied as an organic
functional layer to a first electrode, ITO, for example.
[0155] Production of an Optoelectronic Component
[0156] The organic functional layer produced can be deposited on a
provided substrate, glass, for example, on which a first electrode
has been applied, with a second electrode being applied
thereto.
[0157] The invention is not restricted by the description using the
working examples or specified combinations of features. Instead,
the invention also encompasses individual new features as such and
also any combination of specified features, including in particular
any combination of features in the claims, even if that feature or
that combination is not itself explicitly indicated in the claims
or working examples.
* * * * *